Metering device

ABSTRACT

A device for accurately metering food. The device includes an outer part and an inner metering part having a dosing chamber and a piston block slideably mounted therein. The housing outer part has three passageways, and the dosing chamber is configured, dimensioned and positioned to alternately connect two of the three passageways of the outer part. The inner metering part is configured, dimensioned and positioned for rotation within the outer part. The outer housing part and the inner metering part are mounted concentrically with the inner metering part and the inner metering part has only one degree of liberty in rotation around a central axis of rotation.

FIELD OF THE INVENTION

This invention relates to an apparatus for metering and dispensingprecise portions of fluid food products like sauce, paste, and cream.More precisely, the present invention relates to a slide piston meteringdevice for performing this function.

BACKGROUND OF THE INVENTION

Existing apparatus and machines for dispensing such fluid food productsin the mass production industry are generally coupled to a productsupply assembly which pressurizes the fluid product at an inlet of themetering device. This enables the device to dispense an appropriateamount of food product at its outlet and onto a conveyor belt or in atray or pouch for filling it with product. The product supply assemblycan for instance include a product container such as a hopper or acanister and a pump, which continuously or alternately extracts the foodproduct from the product container and supplies it to the metering anddispensing device under a pressure level that depends on productviscosity, the amount to be dispensed, and the expected production rateof the line.

Many food products require an accurately measured amount of a filling tobe inserted into pouches and trays or as ingredients in the preparationof meals and cakes of every sorts. Previously this has been done by handwhich is extremely expensive and time consuming. However, it isnecessary that the amount of dispensed food product remains constant andaccurate. Indeed, when the receiving medium is over-filled or covered,the manufacturer would have product loss and increased production andraw material costs. To the contrary, when the receiving medium is notprovided with sufficient product, the recipe would not meet thecustomers' expectations.

Several devices and apparatuses have already been developed foraccurately metering and dispensing fluid food products. U.S. Pat. No.5,850,946 relates to a metering device featuring a rotatable meteringelement in the form of a ball with at least one transverse borecontaining a shuttling ball acting as a piston, which can be used formetering gases, liquids and solid particles. The metering element iscoupled to a drive shaft and held captive in a casing having oppositepassages for inlet and outlet flow of the metered product. In operation,a fluid to be metered is supplied via inlet port and acts on theshuttling ball in the rotating element so that it traverses the rotatingelement from an extremity to the other, thus dosing a volumetric shot offluid and expelling an equal volume of fluid via outlet port to adispensing device. Then, a rotation of 1800 of the rotating element isachieved thanks to the drive shaft, and the shuttling ball is againpushed down the bore, dosing a second volumetric shot and expelling thefirst shot dosed. This is repeated as necessary for dispensingadditional dosages or amounts of product.

Such a metering device has an advantage in that it allows for very quickand accurate metering of fluids. However it also constitutes acomplicated assembly of many distinct elements which makes it difficultto maintain in case of problems. Furthermore, only very small amounts offluid product can be dosed and expelled in each working cycle of thedevice. This does not make such a metering device suitable for foodfluid product metering and dispensing in a high quantity food productionline. Due to its small capacity, such a metering device is further notsuitable for metering semi-fluidic products having food particlestherein, such as fruits or meat particles in pies, cream or yogurt, asthe device would rapidly be clogged with food in operation. Finally, itis not possible to dose and dispense more than one type of fluid productwith the same metering device to increase the production rate of theline.

A possibility to dispense several portions of product with a singlemachine is disclosed in U.S. Pat. No. 2,551,419, which describes afilling machine for bakery products. A piston provides a pressure on thefilling material that is dispersed through a manifold, while a series ofvalve-controlled ports then releases the product onto a conveyer belt.One shortcoming of this device is that is does not provide for accuratemetering of the food product. Another filling device with more than oneoutlet port is shown in U.S. Pat. No. 4,830,068. This filling machine iscapable of simultaneously filling recipients on two separate productionlines running in parallel. Dosing and dispensing of the product isachieved by means of a dosing piston and a rotating valve, which aims atregulating the flow of product pressurized by the piston to paralleloutlets for dispensing. A major drawback of the device disclosed in U.S.Pat. No. 4,830,068 is that a precise and controlled metering of theproduct to be dispensed cannot be achieved, and the relatively largesize of the machine makes it difficult to implement in a mass productionline.

Metering systems based on a slide piston are already known in the art,as for example from U.S. Pat. No. 5,456,298. This patent documentdiscloses a metering apparatus comprising a metering head havingdiametrically opposite input and output passageways separated by acylindrical chamber. In the cylindrical chamber is a rotating diskhaving a passageway that passes diametrically through it and a pistonsliding within the disk passageway so that it is simultaneouslydisbursing and filled with product when it is in alignment with theinput and output passageways and then rotated 180°. However, these knownsystems are rather slow, they do not offer dosing versatility and theycause cavitation problems due to the backstroke of the filler.

Considering the above-mentioned shortcomings of the existing meteringand dispensing systems, improvements in such devices are needed.

SUMMARY OF THE INVENTION

The present invention provides a metering device for accurately meteringand dispensing fluid and semi-fluidic products ranging from water toyogurts to thick sauces with or without food mass particulates such asspaghetti-O's or Bolognese-type spaghetti sauces.

The metering device of the present invention provides for increasingproduction and operating speeds of a food product production line thatincludes a filling or depositing stage of a fluid or semi-fluidic foodproduct.

The present invention also discloses a metering device which can be usedin multiple operating configurations without modification of itsstructure. Particularly, the metering device of the present invention iscapable of dispensing one or two doses of a fluid or semi-fluidicproduct from a single source, or alternatively, of metering twodifferent products from two different sources and dispensing them in asingle outlet dose. The metering device of the invention can thus bechosen to dispense food product in different operating configurationsdepending upon the particular dosing needs.

The present invention can exert a positive pressure on the flow ofproduct in order to prevent cavitation, especially when working withhot/warm food, as it is known that cavitation is usually at the originof dosing accuracy problems. A further feature of the present inventionis to provide a metering device which can work in conjunction with afood product supply assembly that is gentle with the food that issupplied to reduce damage on the food and increase the range of foodable to be supplied therefrom.

These features are obtained in improved metering systems that have arotating metering head with a slide piston mechanism therein. Inparticular, these systems utilize a device that includes an outer partand an inner metering part having a dosing chamber and a piston blockslideably mounted therein. The housing outer part has three passageways,and the dosing chamber is configured, dimensioned, and positioned toalternately connect two of the three passageways of the outer part. Theinner metering part is configured, dimensioned and positioned forrotation within the outer part. The outer housing part and the innermetering part are mounted concentrically with the inner metering partand the inner metering part has only one degree of liberty in rotationaround a central axis of rotation.

One characteristic of the present invention lies in the particularconfiguration of the three passageways of the outer metering part. Thesepassageways are arranged at an angular location of between 90° to lessthan 180° from each other around the periphery. The inner metering partis further designed so that the dosing chamber can connect alternatelytwo of the three passageways in two different positions symmetrical tothe axis of the third passageway, and this by consecutive alternatemotion of the metering part in the clock and counterclockwisedirections. For this purpose, the outer housing part and the innermetering part are mounted concentrically, with the inner metering havingonly one degree of liberty in rotation within the outer part.

Preferably, the passageways are arranged at a angular location of from100° to 140° from each other and the chamber is arranged across theinner metering part so as to connect two of the three passageways of theouter part upon each alternate rotation. Also, the dosing chamber ispreferably linear and arranged across the inner metering part so as toconnect consecutively two of the three passageways of the outer meteringpart in two different positions that are symmetrical to each other withrelation to the axis of the third passageway upon each alternaterotation of the inner metering part. Thus, every half-cycle of acomplete operating cycle of the device results in the simultaneousfilling and discharging of the same amount of a food product. The devicecan have has one inlet passageway and two outlet passageways or twoinlet passageways and one outlet passageway, as desired.

A first advantage of such a configuration of the metering device of theinvention is that doubling the capacity and operating speed of thedevice is possible as filling and dosing of product is achieved everyhalf-cycle when it is only done once with the device of U.S. Pat. No.5,456,298. Then, a further advantage of the metering device of thepresent invention is that the number of the passageways and arrangementof the passageways relative to one another provide a versatility of useof the device, i.e., that it can be used either in a 1:2 or 2:1 dosingconfiguration. In a 1:2 dosing configuration, a first passageway servesas a product inlet while the two others serves as two outlets for dosingproduct on two parallel production lines, and in a 2:1 dosingconfiguration two different products can be combined to make a third oneand dose it through a single outlet.

A method for preparing a final food product is also disclosed. In thismethod, at least one fluid food product is directed to one of thedevices according to the invention so that the fluid food product(s) canbe accurately metered and dispensed therefrom to assist in preparing thefinal food product. When the device is provided with one inletpassageway and two outlet passageways, the fluid food product can bemetered and dispensed onto two adjacent production lines. Alternatively,when the device is provided two inlet passageways and one outletpassageway, two fluid food products can be metered and dispensedsimultaneously.

Additional features and advantages of the present invention aredescribed in, and will be apparent from, the following DetailedDescription of the Preferred Embodiments and the figures.

BRIEF DESCRIPTION OF THE FIGURES

The features and advantages of the present invention will be discussedin the further detailed description of the invention with reference tothe accompanying drawings, wherein:

FIG. 1 is a cross-sectional view of the metering device of theinvention, showing the inlets/outlets and a rotating metering headcomprising a slide piston, a metering chamber bored in the head andcontaining the slide piston, and an outer cylindrical part encasing themetering head;

FIG. 2 is a cut away view of the metering head of the metering device ofthe invention;

FIG. 2 a is a side view of one half of the metering head with the slideblock removed;

FIG. 2 b is a perspective view of the metering head of FIG. 2 a;

FIG. 3 is a cross-sectional view of the metering device showing themetering chamber completely discharged an the rotating metering head ina first filling position with a food product forced at the inlet of thedevice;

FIG. 4 is the same view as FIG. 3 but showing the piston slid to theopposite end of the metering chamber being now completely filled withfood product;

FIG. 5 is the same view as FIG. 4 but showing the metering head of thedevice rotated 120° counter clockwise to a second position;

FIG. 6 is the same view as FIG. 5 but showing the metering head in asecond position for discharging a first dose of food product through anoutlet of the metering device and for refilling of the chamber;

FIG. 7 is the same view as FIG. 6 but showing a second filling of themetering chamber and a simultaneous discharging of a same amount of foodwith the piston slid down;

FIG. 8 is the same view as FIG. 7 except with the rotating metering headfilled with product and being rotated 120° clockwise back to the firstposition;

FIG. 9 shows the metering head back in the first position fordischarging of a second dose of food product through a second outlet ofthe metering device and simultaneous recharging of the chamber;

FIG. 10 is the same view as FIG. 9 but showing the metering head at theend of a working cycle of the metering device with the metering chamberrefilled with product and a second dose of product discharged in asecond outlet of the device;

FIG. 11 shows a first preferred embodiment of the metering device of theinvention coupled to one feeding pump in a one inlet and two outletsconfiguration;

FIG. 12 shows a second preferred embodiment of the metering device ofthe invention coupled to two feeding pumps in a two inlets and oneoutlet configuration.

DETAILED DESCRIPTION OF THE INVENTION

The term “fluid food product” is used in its ordinary sense to coveressentially any liquid edible material. In preferred embodiments, thisterm is intended to encompass viscous liquids, such as spaghetti sauce,gravies, creams and the like. In addition, the term also contemplatesadditions to the fluid food products such as particles of meat, pasta,rice, etc. provided that these particles are carried by a liquid.

Referring first to FIG. 1, the metering device 1 of the presentinvention comprises a first cylindrical part forming a housing 2 for asecond cylindrical part having a smaller diameter than the housing 2 andforming a metering head 3. The metering head 3 is coaxially mounted inthe cylindrical housing 2 in a concentric manner such that it has onlyone degree of liberty in rotation around an axis X passing by the centerof the circular faces of the housing 2 and the metering head 3. Thehousing 2 is further bored with three passageways situated at an angleof between 90 to less than 180 degrees from each other around itsperiphery for the purpose of connecting three tubes 4, 5, and 6 forfeeding the metering device with product and respectively dischargingdepending on a chosen configuration of use of the device.

In one embodiment, the three passageways are separated by an angle ofbetween about 100 to 140 degrees from each other, and more preferably ofabout 120 degrees as shown in FIG. 1. A main advantage of having threepassageways situated at about 120° from each other is that it gives themetering device of the invention a versatility feature. Indeed, it canbe used either in a 1 to 2 (or 1:2) dosing configuration, i.e., with oneinlet 4 and two outlets 5 and 6 or in a 2 to 1 (or 2:1) dosingconfiguration, i.e. with two inlets 5 and 6, and one outlet 4. Thedosing configuration can be obtained by merely reversing the dosingdirection of the device and does not require any changing of themetering head. Therefore, in a 1:2 dosing configuration of a firstembodiment of the invention shown in FIG. 11, two separate doses of aproduct can be dispensed onto parallel running lines without the use ofmanifolds whereas, in a 2:1 dosing configuration of a second embodimentshown in FIG. 12, two different products can be combined and dosed at a50:50 rate with a great accuracy through the same outlet for dispensinginto a common zone.

The metering head 3 is rotatable within the housing 2 and it can be madeof two separate symmetrical halves 7 a, 7 b fastened to each other bymeans of detachable connection means such as screws 10, three of whichare shown in FIG. 2. Inside, the metering head includes a slide pistonmechanism which is composed of a slide block 8 capable of sliding alonga dosing chamber 9 formed by identical and complementary portionsscooped out in the two halves 7 a, 7 b of the metering head 3. The slideblock 8 and the dosing chamber 9 preferably have a cylindrical designand, when the two halves 7 a, 7 b are connected together, the dosingchamber 9 extends within the metering head in a manner suitable forconnecting consecutively two of the three passageways in the housingpart 2 in two different positions, symmetrical to each other withrelation to the axis Y of the third passageway upon rotation of themetering part 3. Moreover, to entrap the slide block 8 in the meteringhead 3, the diameter of the emerging ends 11 a, 11 b of the dosingchamber must be smaller than the diameter of the slide block 8 and thedosing chamber 9 themselves, so as to form indentations that retain theslide block 8 in the dosing chamber 9.

Referring now to FIGS. 3 to 10, a complete operating cycle will bedescribed in details for a first working configuration of the meteringdevice of the invention.

As seen in FIG. 3 for a 1:2 dosing configuration of the metering deviceaccording to the invention, a fluid or semi-fluidic food product 12 issupplied under pressure at an inlet of the metering device 1 through aninlet tube 4 of the housing 2. The metering head 3 is in a first fillingposition, hereafter called position “A”. The dosing chamber 9 iscompletely empty, the slide block 8 in an upward position and theemerging end 11 a of the dosing chamber 9 communicates with the inlettube 4 while the opposite emerging end 11 b communicates with a firstoutlet tube 6 of the device. Under the pressure of the food product 12the slide block 8 is pushed to the second emerging end 11 b towards thedosing chamber 9, which is consequently filled with a first dose of foodproduct as shown in FIG. 4. As the emerging ends 11 a, 11 b have asmaller diameter, the slide block is stopped in a backward position andkept under pressure of the food product when it reaches emerging end 11b of the dosing chamber 9, thus ensuring that an accurate amount ofproduct has filled the cavity. The metering head 3 is then rotated about120° counterclockwise, as it is represented in FIG. 5, to a secondposition symmetrical to position A and hereafter called position “B”.

As shown in FIG. 6, in position “B” the slide piston mechanism isinverted compared to position “A”. The slide block 8 is again in anupward position but now the emerging end 11 a is communicating with thesecond outlet tube 5 of the metering device while emerging end 11 bcommunicates with the inlet tube 4 where the food product iscontinuously forced in. The dosing chamber 9 is subsequently filled asecond time while at the same time the first dose of product filled inposition “A” is disbursed through the outlet tube 5 under the action ofthe slide block 8 forced down by the product as shown in FIG. 7. Then,the metering head 3 is rotated 120° clockwise back to position “A” asshown in FIG. 8. Another simultaneous action of filling and dischargingan equal amount of food product in and from the dosing chamber 9 occursthrough the second outlet tube 6, completing one operating cycle of themetering device of the invention as shown in FIG. 9 and FIG. 10. Itcontinues then to rotate back and forth, dosing and filling exactly asame amount of food product all in one motion every halves of a workingcycle.

According to the above description of an operating cycle, a second mainadvantage of the present metering device over the conventional pistonmetering apparatuses is that it allows for doubling the operating speedand thus the production rate of the device as compared with the priorart. Indeed, with the device disclosed for example in U.S. Pat. No.5,456,298, there are only one inlet and one outlet to the device,creating the need to rotate the metering head 180° backward and forwardto fill and then disburse the product. Thus it takes one completeoperating cycle to dispense a single dose. With the present meteringdevice rotating the metering head of 120° allows to complete filling anddischarging of the dosing chamber in a same motion every half-cycle ofthe system, therefore dosing twice in one full cycle whateverconfiguration of the device were, i.e. a 1:2 or a 2:1 dosingconfiguration.

It is thus possible to dispense at a speed of up to 120 doses of productper minute, which represents an operating speed of the device almosttwice the speed of conventional piston metering devices actuated bypneumatics like the one of U.S. Pat. No. 5,456,298.

Turning again to FIG. 2, the volume of product to be dosed in themetering head 3 can easily be adjusted depending on the needs, byvarying the length of the slide block 8 so that it takes more or lessroom in the dosing chamber 9. This can be done by simply removing themetering head 3 from the housing 2, unscrewing the three screws 10fastening the two halves 7 a, 7 b of the metering head 3 together andchanging the slide block 8 placed inside the metering head 3.Furthermore, all the elements constituting the metering device of theinvention are preferably made of food grade materials, such as plasticsand metals such as stainless steels, which materials can also be easilymolded and processed at low costs.

Another advantage of the metering device of the invention over the priorart is that the operating speed and accuracy of the dosing unit are keptconstant by maintaining a positive pressure on the flow of product atthe inlet of the metering device. Indeed, a limiting factor withconventional piston metering device fed with pumps is that a cavitationphenomenon usually occurs due to the backstroke of the piston,particularly when working with warm/hot fluid or semi-fluidic products.Cavitation is a hydraulic condition, which can exist with any type ofpump and which corresponds to the formation of gas or vapor cavitiesinto a moving fluid when the pressure at one point of the fluid becomeslower to the vapor tension of that fluid.

In the metering device of the invention, any cavitation is prevented byusing a double-diaphragm pump 12 for feeding the food product at theinlet 4 of the metering device 1 with a constant pressure as shown inFIG. 11, representing a first preferred embodiment of the invention withthe metering device used in a 1:2 dosing configuration. Supplyingproduct from a supply 16 with a constant pressure could be achieved withany type of positive displacement pumps like for instance rotary lobepumps. However, and additional advantage of using a double-diaphragmpump 12 for supplying the metering device 1 of the invention is that thediaphragm construction prevents the product from being damaged.Particularly, in the case of processing semi-fluidic food product havingfood mass particulates therein, the use of a diaphragm pump gentlyhandles the product whereas it would be crushed into rotary pumps. Instating this, the range of product processed and dosed with the meteringdevice of the invention can vary from totally liquid products like wateror milk to thicker fluids as well as sauces and gravies with large foodparticulates therein, such as, for example, spaghetti O's, meat sauces,rice pudding, and the like. Furthermore, by using a diaphragm pump tofeed the metering device the output product pressure from the pump tothe inlet of the metering device is directly proportional to the airpressure used to actuate the pump. Thus pressure from at least about onepsi to about 120 psi can be applied at the inlet of the metering devicedepending on the viscosity and particulate mass of the product to bedosed.

In the case the metering device is used in a 2:1 dosing configuration asshown in FIG. 12 for a second preferred embodiment of the invention, twoseparate diaphragm pumps 13 and 14 must be used to feed the products ateach separate inlet 5 and 6 of the metering device 1. Thus anappropriate product pressure is applied at each inlet of the meteringdevice to ensure the accuracy of the metering of each productindependently depending on their physical characteristics for dispensingthe product exactly at a 50/50 rate through the single outlet 4 of themetering device. The outlet 4 may be connected to a terminal dispensinghead 18 that dispenses the product on a point of dispense such as a foodtray travelling on a conveyor belt.

Coupled to the metering head of the device according to the presentinvention is also a trigger assembly for the purpose of driving themetering head of the metering device in rotation to actuate the meteringdevice. The trigger assembly can conveniently be a pneumatic systemincluding an air-actuated solenoid triggered by a sensor-controller. Butif the metering device of the invention is to be used in a very enclosedenvironment, the metering head can also conveniently be electronicallydriven by means of a servo requiring a signal input from asensor-controller. Alternately, when the metering is used in-line with aconveying system for metering and products directly into recipients, themetering head can also mechanically set in time with the productconveying system in order to control the metering action with respect tothe advancement of the conveying system.

The metering device according to the present invention has beendescribed in what is considered to be the most practical and preferredembodiments. However, it may be subject to many alternatives andmodifications, which could become evident to the skilled artisan butwithout departing from the spirit and the scope of the inventionclaimed.

It should be understood that various changes and modifications to thepresently preferred embodiments described herein will be apparent tothose skilled in the art. Such changes and modifications can be madewithout departing from the spirit and scope of the present invention andwithout diminishing its intended advantages. It is therefore intendedthat such changes and modifications be covered by the appended claims.

1. A device for accurately metering a product comprising a housing outerpart and an inner metering part having a dosing chamber and a pistonblock slideably mounted therein, the housing outer part comprising threepassageways, and the dosing chamber being so constructed and arranged soas to alternately connect two of the three passageways of the outerpart.
 2. A device according to claim 1, wherein the inner metering partis configured, so constructed and arranged so as to rotate within theouter part.
 3. A device according to claim 2, wherein the outer housingpart and the inner metering part are mounted concentrically with theinner metering part and the inner metering part has only one degree ofliberty in rotation around a central axis of rotation.
 4. A deviceaccording to claim 2, wherein the passageways are arranged at an angularlocation of from 90 to less than 180 degrees from each other and theinner metering part includes a chamber arranged across the part so as toconnect two of the three passageways of the outer housing part upon eachalternate rotation of the inner metering part.
 5. The device accordingto claim 4, wherein the passageways are arranged at a angular locationof from 100 to 140 degrees from each other and the chamber is arrangedacross the inner metering part so as to connect two of the threepassageways of the outer part upon each alternate rotation.
 6. Thedevice according to claim 4, wherein the passageways are arranged at aangular location of approximately 120 degrees from each other and thechamber is arranged across the inner metering part so as to connect twoof the three passageways of the outer part upon each alternate rotation.7. The device according to claim 4, wherein the dosing chamber is linearand arranged across the inner metering part so as to connectconsecutively two of the three passageways of the outer metering part intwo different positions that are symmetrical to each other with relationto the axis of the third passageway upon each alternate rotation of theinner metering part.
 8. A device according to claim 1, wherein everyhalf-cycle of a complete operating cycle of the device results in thesimultaneous filling and discharging of the same amount of a foodproduct.
 9. A device according to claim 1, wherein the dosing chamberincludes emerging ends that form recesses to entrap the piston block inthe inner metering part.
 10. A device according to claim 1, having oneinlet passageway and two outlet passageways.
 11. A device according toclaim 1, having two inlet passageways and one outlet passageway.
 12. Amethod for preparing a final food product, comprising the steps ofdirecting at least one fluid food product to a device comprising ahousing outer part and an inner metering part having a dosing chamberand a piston block slideably mounted therein, the housing outer partcomprising three passageways and the dosing chamber being so constructedand arranged so as to alternately connect two of the three passagewaysof the outer part so as to accurately meter and dispense the fluid foodproduct(s) therefrom to assist in preparing the final food product. 13.The method of claim 12 wherein the device has one inlet passageway andtwo outlet passageways so that the fluid food product can be metered anddispensed onto two adjacent production lines.
 14. The method of claim 12wherein the device has two inlet passageways and one outlet passagewayso that two fluid food products can be metered and dispensedsimultaneously.
 15. The method of claim 12, wherein the inner meteringpart is so constructed and arranged to allow for rotation within theouter part to meter and dispense the fluid food product.